Aircraft engine and fuselage arrangement



April 18, 1950 c. JOHNSON ET AL 2,504,422

AIRCRAFT ENGINE AND FUSELAGE ARRANGEMENT Original Filed April 25. 1946 3 Sheets-Sheet 1 INVENTORS. CLARENCE L. JOHNSON WILLIS M. HAWKINSJR. ALONSO B.STOREY JR. y

April 18, 1950 c. L. JOHNSON ET AL 2,504,422

AIRCRAFT ENGINE AND FUSELAGE ARRANGEMENT Original Filed April 25, 1946 3 Sheeqs-Sheet 2 INVENTORS. CLARENCE L. JOHNSON W|| |s M. HAWKINS JR. 4ALONSO B. STOREY JR.

April 18, 1950 0.1.. JOHNSON ET AL 2,504,422

AIRCRAFT ENGINE AND FUSELAGE ARRANGEMENT Original Filed April 25. 1946 3 Sheets-Sheet s WILLIS M. HAWKINSJR, ALONSO B.STOREY JR.

3 of battle damage or rupture of the tail pipe, such induced flow also serving to purge the tail pipe in fiight after the engine has stopped.

As best shown in Figure 4, the tail pipe I4 is detachably secured at its front end to its diaphragm 23, the rear end being slidably mounted in a bulkhead ring 32 because the tail pipe grows or lengthens over an inch when at oper ating temperatures. Because of the critical temperature conditions in the tail pipe, it is preferably arranged as shown in the detailed section of Figure 5, wherein inner and outer shells,

33 and 34 of stainless steel, are separated by suitable insulation, to be described in more detail hereinafter. The outer shell 34 carries a series of flanged hoops 35 and 36 to maintain the assembly against flattening or collapse of the hoop 36 serving as a sliding surface under the bulkhead ring 32.

Because of the crtical temperature range in the tail pipe, the problem of insulation thereof without excessive weight penalty has proved particularly difiicult to solve. We have found that the use of certain light-weight insulating materials may permit floating of the inner shell 34 due to the tendency of the insulation to flow. In one case a floating force of 160 pounds, much more than the weight of the inner shell, tended to distort or bow the latter as the insulation tended to work "down underneath the inner shell, leaving the upper portion uncovered. In order to overcome this floating tendency in connection with displaceable insulation, we have provided a plurality of load bearing rings comprising a central core of amosite 3?, a South African species of asbestos, having superior heat resistance, either wrapped in a sheet of woven fiber glass 38 and wound with Inconel wire at one-quarter inchpitch, or enclosed in a knitted tube of Inconel wire, the stretching of such a knitted wire tube serving to compact the amosite filling.

Between such bearing rings, the best combination of light-weight and insulation properties is a composite blanket comprising an inner layer of leached Woven fiber glass fabric 39, a second felted layer of fiber glass textile scrap 4|, and this felted layer of leached fiber glass fabric 4B and an enclosing outer layer of unleached fiber glass fabric 42. Leached fiber glass is a relatively new material wherein acid is used to remove the boron and alkali constituents leaving quartz. Ordinary glass fiber has a softening point of about 1500 F. and becomes brittle at 1300 F. whereas such glass fibers when acidleached, leave a molecular silica skeleton of greatly reduced strength, but with greatly increased refractoriness, to heat, tests having shown that no fusing of fibers occurs at 1900 F.

The central layer of glass fabric scraps is used primarily for bullet sealing purposes, as we have found that bullets penetrating the tail pipe assembly tend to pull such fabric scraps into the hole, substantially plugging the same. This arrangement serves to protect the enveloping airplane structure from heat and corrosive damage due to possible leakage of the hot gas blast in the tail pipe.

Having described only a typical form of the invention we do not wish to be limited to the specific details herein set forth, but wish to reserve to ourselves any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.

We claim:

1. In combination with an airplane fuselage and a power plant therefor, a removable tail section forming a continuation of said fuselage, said power plant being located within the fuselage adjacent the junction of said tail section therewith, means for joining said tail section to the balance of said fuselage including at least a portion of a mounting means for said power plant whereby said mounting means will be exposed for ready removal of said power plant upon disconnection and removal of said tail section, a power plant exhaust tail pipe axially disposed in said tail section and separable as a unit therewith, and means for supporting said exhaust tail pipe in said tail section adapted to permit longitudinal thermal expansion thereof.

2. In an airplane wherein a power plant has mounts attached to the airplane fuselage, means providing a quickly demountable transvers fuselage joint adjacent the power plant mounts whereby removal of the rear portion of the fuselage facilitates access to and removal of the power plant from the forward portion of the fuselage, a tail pipe adapted to receive the exhaust from the power plant, said tail pipe being disposed axially through the rear portion of the fuselage and removabl as a unit therewith, and mounting means for said tail pipe comprising a diaphragm adjacent the forward end thereof for maintaining the tail pipe in alignment with the power plant, and a, sliding support adjacent the rear end thereof adapted to permit longitudinal expansion of said tail pipe.

3. In combination with an airplane fuselage having a body section and a removable tail se"- ticn, a power plant located within the fuselage adjacent the junction of said body and tail sections, cooperating bulkhead rings carried by said body and tail sections, means for detachably connecting said bulkhead rings to detachably connect said fuselage sections, means including said bulkhead rings for mounting said power plant, whereby said mounting means will be exposed for ready removal of said power plant upon disconnection and removal of said tail section, and power plant exhaust tail pipe axially disposed in said tail section and separable as a unit therewith.

4. In combination with an airplane fuselage having a body section and a removable tail section, a power plant located within the fuselage adjacent the junction of said body and tail sections, cooperating bulkhead rings carried by said body and tail sections, means for detachably connecting said bulkhead rings to detachably connect said fuselage sections, means including said bulkhead rings for mounting said power plant, whereby said mounting means will be exposed for ready removal of said power plant upon disconnection and removal of said tail section, a power plant exhaust tail pipe axially disposed in said tail section and separable as a unit therewith, and means for mounting said tail pipe in said tail section to provide for longitudinal thermal expansion thereof.

CLARENCE L. JOHNSON. WILLIS M. HAWKINS, J R. ALONZO- B. STOREY, JR.

No references cited. 

